'Pac-Man' Enzyme Reduces The Half-Life Of Nicotine, Offers New Hope For People Trying To Quit Smoking
Scientists at The Scripps Research Institute (TSRI) may have just found another weapon in the fight against nicotine addiction, and it works a lot like your favorite video game: Pac-Man.
The weapon is NicA2, a bacterial enzyme that prevents nicotine from reaching the brain, which reduces the "reward" associated with persistent smoking habits and relapses. Study author Kim Janda, a chemistry professor and member of the Skaggs Institute for chemical biology at TSRI, admitted that the research is still in the early stage of development, but the results so far are promising. The enzyme has already demonstrated the properties necessary for successful anti-smoking therapy. The enzyme would also offer an alternative to current smoking cessation aids, which studies have shown fail in about 80 to 90 percent of smokers.
Janda and his colleagues have been trying to create such an enzyme in a lab for over 30 years, only recently uncovering NicA2 from the bacteria Pseudomonas putida; it's originally isolated from soil in a tobacco field. And NicA2 consumes nicotine as its sole source of carbon and nitrogen.
"The bacterium is like a little Pac-Man," Janda said. "It goes along and eats nicotine."
The researchers tested the enzyme for any therapeutic qualities it may have. First, they combined a component of blood with a dose of nicotine equal to one cigarette. When they added the enzyme, the nicotine’s half-life dropped from two to three hours to just 9 to 15 minutes. A higher dose of the enzyme — plus a few chemical modifications — could reduce the half-life of nicotine even further and stop it from reaching the brain altogether.
Then, researchers further tested the enzyme to see if it could be developed into an anti-smoking drug. The enzyme was stable in a lab for over three weeks at 98 degrees Farneheit, which, according to Janda, is “pretty remarkable.” Better yet, there were no toxic metabolites leftover after the enzyme ate the nicotine.
“It was a long shot,” Janda said. “If it didn’t have the right metrics, it would be a bust.”
Janda said the next step is to alter the enzyme’s bacterial makeup, which will help lessen potential immune problems and maximize its therapeutic potential.
Source: Janda K, Xue S, Schlosburg J. “Characterization of a Bacterial Enzyme for the Degradation of Nicotine. Journal of American Chemical Society. 2015.